Process for removing solvent from solvent-wetted vegetable residues



April 4, 1950 H. F. SAUNDERS 2,502,434

PROCESS FOR REMOVING SOLVENT FROM SOLVENT-WETTED VEGETABLE RESIDUESFiled Sept. 11, 1947 2 Sheets-Sheet l MIXTURE AGITA TED sows/4r SOLVENTREMOVAL BY HEAT & PARTIAL VACUUM SEPARATION OF SOL/D5 PRECIPITATING FROMAQUEOUS LIQUID AGENT W/IjH/IVG PRECIPITATION OF 0F SOLIDS SOLUBILIZEDMATERIAL IN LIQUID SOLIDS PRODUCT SEPARATION 0F,$OLID$ "a" FROM AQUEOUSLIQUID WASHING OF LIQUID SOLIDS PRODUCT SOLIDS PR ODUCT INVENTOR HaroldE Saunders ATTORN EYS April 4, 1950 H. F. SAUNDERS, 2,502,484 I PROCESSFOR REMOVING SOLVENT FROM SOLVENT-WETTED VEGETABLE RESIDUES Filed Sept.11, 1947 2 Sheets-Sheet 2 VEGETABLE RES/DUES- WETTED WITH ORGANICSOLVENT AQUEOUS LIQUID SOLVENT MIXTURE AGITATED SOLVENT REMOVHL BY HEAT& PARTIAL VACUUM PREfIEI/Ty'giT/NG i PRECIPITATION 0F sows/1.1250MATERIAL IN uqum SEPARATION OF .SCMJDS FROM AQUEOUS LIQUID Harold ESaunders ATTORN EYS more volatile than water.

Patented Apr. 4, 1950 PROCESS "FOR REMOVING SOLVENT FROM SOLV-ENT-WETTEDVEGETABLE RESIDUES Harold F. Saunders, Shaker Heights, Ohio, as-

signor to The Sherwin-Williams 00., Cleveland, Ohio, a corporation ofOhio Application september 11, 1947, Serial No. 773,481

' 1 This invention relates to improved processes for removing sol-ventfrom solvent-Wetted vegee table residues, such as those remaining aftersolvent extraction of oils and fatty materials from oil-containingvegetable materials, and to prod ucts, containing ,proteinaceousmaterials, pros duced from such solvent-wetted. residues.

Such oil-containing vegetable materials are seeds, beans, nuts andleaves containing proteinaceous material and a substantial proportion ofoil. Examples are cottonseed, castor beans, soya beans, peanuts,flaxseed, hempseed, sunflower seed, oiticia nut, tungnut, coconut, andthe like.

Processes are widely used ,for extracting oils and fatty materials fromsuch vegetable materials by means of organic solvents-which are'usual'lyAfter the vegetable material has been treated with asolvent for theextraction of oil, there remains a solvent-wetted residue which issubstantially insoluble in the solvent employed. ,Such residues usuallycontain cellular material, proteins, carbohydrates such as sugars,mucilages, and a small proportion of water, in a more or less finelydivided state. The particle size may range from colloidal dimensionsto aquarter inch or more. If the cortex or shell was not removed prior tosolventtreating,

this material will also be contained in the residue. Thesolvent-wettedresidues may be in the form of a cake or a solvent-slurry.

Recovery of the solvent from such residues is highlydesirable both foreconomic reasonsand to render the residues or proteinaceous -materialsderived therefrom more useful. The reeovered solvent usually isre-employed in the solvent extraction process. Heretofore, recovery ofsolvent from the residues has been customarily efifected by directlyheating the solvent-wetted residues to volatilize the solvent, which issubsequently con densed for reuse. Although the solvents usuallyemployed have boiling points below 100 C., it is nevertheless generallynecessary to use temperatures of about 120 :C. or more'to achieve rapidand completeremoval of thesolvent from the residues. The use of thesehigh temperatures often results in charring or degradation of theresidues and deleterious efiects upon the proteinaceous materials in theresidues, particularly when water is present. .Such deleterious eifects.on the proteinaceous materials make it very diiiicult or impossible todisperse the final products in acidic, salt or alkaline solutions, as isoften. desirable when using these products. Because the odor and/ortoxicity of the solvent would renderresidues unfit for stock food, ithasbeen usually 14 Claims. (Cl. 260-1235) necessary to expose the residuesto high temperatures for prolonged periods to eiiect complete removal ofthe solvent. This increases the possibility of charring or degradationof the residues and harmful effects on the proteinaceous materials.

When the products are to be used in paints, coating materials, adhesivesand the like, it is often desirable to mix them with aqueous liquids toform'dispersions or emulsions. The practices heretofore employed inchanging the solventwetted residues to water-wetted products haveinvolved first heating the residues to substantially complete dryness toremove all of the solvent, and subsequently mixing the dried residueswith an aqueous liquid. Drying the residues substantially reduces theirdispersibility or solubility in water, particularly when the drying iscarried out in the presence of water. This prior manner of converting asolvent-wetted material to a water-Wetted material is thus not onlydiflicult and expensive, but also results in poorer dispersioncharacteristics of the water-wetted material.

It is an object of the present invention to provide processes forremoving residual solvent from solvent extracted vegetable materials,which eliminate the above-mentioned disadvantages.

It is another object of this invention to remove solvent from suchsolvent-wetted residues without using high temperatures or prolongedheating periods as is required by direct heating; thus eliminating thedeleterious efiects of overheatmg.

'Itis a further object of this-invention to transform the solvent-wettedresidues or the proteinaceous' materials derived therefrom to a water-Wetted product without drying the material so that the dispersibility orsolubility is not impaired.

Another object of the invention is to provide novel products containingproteinaceous materials, including concentrated proteinaceous materialsubstantially free of cellular material and cortex, which products areextremely de.- sirable for many purposes.

According -tothe present invention, solventwetted vegetable residues areheated, while in admixture with an aqueous liquid, to a temperaturesufficientto vaporize the solvent. The aqueous liquid is such that it.dissolves or disperses a substantial proportion of the proteinaceousmaterial in the residues. The aqueous liquid may be water, :an aqueoussolutionlof a neutral salt, an aoueous acidicsolutionorpreferablyanaqueous alkaline solution which is better capable 3 of dispersing theproteinaceous materials. Advantageously, the mixture of residue, solventand aqueous liquid is subjected to a partial vacuum to assistvaporization of the solvent from the mixture while it is being heated toa temperature below that which will adversely affect the residues or theproteinaceous materials in the residues. Preferably, the mixture issubjected to heat and partial vacuum until substantially all of thesolvent has been removed from the mixture. The resulting mixture ofaqueous liquid and residues which is substantially free of solvent maybe used as such, or after removal of some or all of the aqueous liquid.However, the mixture may be treated further to precipitate certainproteinaceous or other materials, either in the presence of residuesolids which are insoluble in the aqueous liquid, or after removal ofsuch solids. Such a solid product may be separated from the aqueousliquid and used wet, or it may be washed, dried and pulverized beforeuse. The separated liquid may be further pro-- cessed, if desired, torecover other useful substances therefrom. The products of the presentinvention may be employed as emulsifying or emulsion stabilizing agentsin paints, coating materials, and adhesives, and as foods andfertilizers, and for many other purposes.

Processes according to the present invention make possible the rapid,efficient and economical removal and recovery of the solvent from thesolvent-wetted residues, and the production at low cost, of high usefulproducts from the residues.

The use of an aqueous liquid in admixture with the solvent-wettedresidues provides several important advantages. For example, the aqueousliquid facilitates dispersion of the residues and, hence, facilitatesvaporization of the solvent from the residues at relatively lowtemperatures so as to avoid harmful effects on the residues orproteinaceous materials therein. The aqueous liquid also solubilizesproteinaceous materials and facilitates their extraction from theresidues.

The above advantages are obtained when the aqueous liquid is water, or aneutral salt solution or an acidic solution, but greater advantages areprovided when an aqueous alkaline liquid is used because of theparticularly good dispersing effect on the proteinaceous materials. Alsoan aqueous alkaline liquid is advantageous since it pronouncedlyinhibits coagulation of heat-coagulable proteinaceous materials duringsolvent removal.

According to the present invention, the solvent is removed fromsolvent-wetted residues, and the residues are converted to a state inwhich they are wet with an aqueous liquid without ever passing through adry state which could impair their dispersibility or solubility. Theproducts of this invention have improved solubility and dispers oncharacteristics so they may be used, for example, in emulsions, paints,coating materials or binding materials, as fillers for plastics or othermaterials, as foods and as fertilizers, etc.

These and other objects, features and advantages of the invention willbe apparent from the following more detailed description of theinvention and the accompanying drawings.

In the drawings,

Fig. 1 represents a flow sheet illustrating one process embodying theinvention; andv 4 Fig. 2 represents a flow sheet illustrating anotherprocess embodying the invention.

NATURE OF SOLVENT-WETTED RESIDUES While the present invention isapplicable to the treatment of solvent-wetted vegetable residues ofvarious kinds, it is particularly useful in the treatment of theresidues remaining after seeds, beans, nuts, leaves, or other vegetablematerials containing substantial amounts of oil and proteinaceousmaterial have been crushed and treated with a solvent for removing oilsand fatty materials therefrom, with or without a preliminary mechanicalpressing process to express oil. Examples of such vegetable materialsare cottonseed, castor beans, soya beans, peanuts, rapeseed, flaxseed,hempseed, sunflower seed, oiticia nut, tungnut, and others.

Because of the crushing, grinding or pressing operations to which theoil-containing vegetable materials are subjected before or while beingsubjected to solvent extraction, and because of the disintegration ofstructure which usually occurs during the solvent extraction, theinsoluble residues remaining after solvent extraction consist of more orless finely divided solids. Such solids are wetted with the solvent,which usually has some oil and/or fatty material dissolved therein andusually contains a small amount of water originating from the vegetablematerials or the solvent. Such solids may be in the form of asolvent-slurry, or a wet cake. The solids comprise cellular material,cortex, unless the seeds or beans were decorticated, proteinaceousmaterial, carbohydrates such as sugars, and mucilages. The solids rangein size from large particles which may be a quarter of an inch or largerin their largest dimensions and which usually are cortex particles, tofines dispersed in colloidal suspension.

The solvents with which the residues are wetted are organic liquids ormixtures thereof having boiling points under standard conditions of fromabout 35 C. to about C. When in admixture with water and when under apartial vacuum, the solvents will vaporize at temperatures below about60 C. whereas the water will not vaporize under the same conditions.Solvents which are generally suitable for the extraction of oil fromvegetable materials can be removed from the residues in this fashion.Such solvents include various oil-miscible organic solvents havingboiling points below about 100 C. For example, aliphatic hydrocarbonssuch as hexane, heptane, and the like, their isomers, chlorinatedderivatives thereof as well as various aromatic solvents such as benzeneand the like have been used for oil extraction.

Solvent-wetted residues of the kind described above, whether in the formof a slurry or cake, may be referred to hereinafter as solvent-wettedpomaces.

FORMATION OF MIXTURE OF AQUEOUS LIQUID RESIDUES In the present processthe solvent-wetted pomaces or residues are first mixed with an aqueousliquid. This aqueous liquidmay. be water, a solution of an alkalinesubstance, a solution of a neutral salt or a solution of an acidsubstance depending upon the desired pH of the final mixture. Forreasons noted hereinafter it is generally preferred to render themixture alkaline, although a neutral or acidic mixture may be preparedwith advantage.

' The mixture of solvent-wetted residues and an aqueous liquid isprepared by mixing the solvent-wetted residues with water and thenadding the alkaline or acidicsubstance or neutral salt or by mixin thesolvent-wetted residues with water while adding a concentrated aqueoussolution of the substance for controlling the pH. The last procedure ispreferred because it is more convenient and the pH may be controlledmore easily;

According to the preferred procedure, water and a concentrated solutionof an alkaline material are added slowly to a solvent-wetted residuewhile it is subjected to rapid stirring to prevent lumping. This isparticularly important when the residue contains substantial amounts ofmucilages. A mixing tank having rotatable shearing blades or paddles maybe used. Suflicient water is added to form a slurry which may behomogenized by circulating it from the tank, through a mixing pump, andback to the tank. A screen may be. employed in the conduit discharginginto the tank, to remove from the slurry agglomerates which may be addedto the next batch for reworking.

The total quantity of water added is sufficient to make an easilyflowahle slurry and depends upon the nature of' the solvent-wettedresidues, the amount and kind of solvent present in the residues, thenature of the products to be made from the residues and the desired pHof the mixture. Generally; it. is advantageous to use from about partsto about 50 parts by weight of" water to one part of solid residues. Thelower pro ortions of water can be employed when the residues have a lowmucilagenous content as in the case of soya bean, castor bean, peanut orcottonseed or when it. is desired to solubilize and extract from theresidues a minimum quantity of proteinaceous material. The higherproportions of water are employed when the residues have a high contentof mucilage as with flaxseed' or when it is desired to solubilize andextract a maximum amount of proteinaceous material.

The pH value of the resulting mixture of aqueous liquid and.solvent-wetted residues is important in controlling the nature of theproducts to be obtained. According to the invention, the mixture mayhave av pH value lying within the range of fromabout 5 to about 13',although beneficial results are obtained even when the mixture has anHvalue above or below this range. Whenthe mixture has a pH value of fromabout 5 to about 8, the aqueous liquid disperses the residues.

and opens up the structure of the solids more efficiently, thus makingpossible the use of low temperatures for removing the solvent, and theproduction of water-wetted products without an intermediate dryingoperation.

However, when the mixture has a pH value of from about 8 to about 13',considerably increased.

advantages are obtained. A pH value in this range greatly aids indispersing the residues; in inhibiting lumping andv agglomeration of theresidues, both during and after removal of the solvent; in'opening upthe structure of the solids in the residues; in solubilizingproteinaceous materials in the residues; in inhibiting coagulation ofheat-coagulable proteinaceous materials during solvent removal; infacilitating release of solvent from the residues, thus permitting theuse of lower temperatures for solvent removal; and" in facilitating.release of proteinaceous materials from the residues. For optimumeffects 6- along these lines a pH value of from about 10 to about 12 ismost advantageous.

The lower pH values may be obtained when the solvent-wetted residues aremixed with water alone, or with an aqueous solution of a suitable,preferably neutral, salt, such as NaCl, NH4C1, K01, Na2SO4, or with anaqueous acidic solution. When a salt solution is used, the salt ispreferably in a concentration of about 5% to about 10%, by weight. If anaqueous acidic solution. is used to obtain amixture havingv low pH,either an acid or a compond giving an acidic reaction can be used, suchas sulfuric acid, hydrochloric acid, sulfurous acid, acetic acid, S02gas, or salts'which produce acidic solutions.

However, when an alkaline solution is desired, a water-soluble alkalinecompound or a watersoluble compound capable of producing alkalinereactions, such as sodium hydroxide, potassium hydroxide, ammoniumhydroxide, sodium carbonate, potassium carbonate, sodium sulfite,potassiurn sulfite, and ammonium sulfite is dissolved in the water.These compounds are readily soluble and, if the mixture is acidified ina subsequent step of the process, as described hereinafter, a solublesalt is formed, thus avoiding undesirable precipitates.

Some of the alkaline components tend to react with constituents of theresidues over a period of time, thus resulting in a lowering of thealkalinity of the aqueous liquid in contact with the residues. Hence, itmay be advisable or necessary to add more alkaline material to themixture, either continuously or from time to time, to maintain the pH atapproximately the value necessary to prevent precipitation of desiredsolu'- bilized materials.

In the mixture prepared as indicated above, the solid residues arepreferentially wetted by the solvent, and they tend to float with thesolvent on the aqueous liquid. In this state, the mixture is filterableonly with the greatest difficu ty and separation of the liquids from thesolids by centrifuging is most ineflicient, since the solids flow offwith the liquid. As the solvent is re'-.

moved by evaporation, the solids in the mixture become preferentiallywetted by the aqueous.

liquid". This change is observed when the solids begin to settle in theaqueous liquid, after which they can be readily separated by filtrationor centrifuging.

It is not necessary to remove all of the solvent to change the wettingcharacteristics of the solids, but for reasons of economy and forremoval of solvent odors from the final product, it is preferred toremove substantially all of the solvent.

REMOVAL OF SOLVENT the solvent, thus permitting the use of low heatingtemperatures. Agitation of the mixture inhibits settling of the residuesand aids in flushing the solvent out from the mixture. As was indicatedabove, low heating temperatures are desirable because they cause little,if any, degradation of the residues or the proteinaceous materials.Solvents of the kind defined. above, may be rapidly and substantiallycompletely removed from the mixture by heating to atemperature nothigher than about C. while under a partial vacuum. When solvents havinglower boiling points are present in the mixture, temperatures within therange from about C. to about C., at a pressure of about 28 inches ofmercury, are sufficient for substantially complete removal of thesolvent.

The removal of the solvent is greatly facilitated if the mixture is inthe form of a film, spray or stream, so that a large surface is exposedto the vaporization condition.

Any type of apparatus or vessel may be used for evaporating the solventthough it is desirable to provide means for introducing the mixture intothe vessel, as a spray or stream, a substantial distance above thenormal liquid level in the vessel. In this case at least a portion ofthe liquid in the bottom of the vessel may be recirculated to the pointof initial introduction for more eflicient and complete removal of thesolvent. The vessel may be heated directly by injecting steam thereintoor indirectly by a heating medium circulated through heating coils orthe like. The solvent vapors are withdrawn from the vessel and condensedfor reuse in the solvent extraction of the vegetable materials.

The mixture is agitated, during removal of the solvent, by the splashingof the fresh or recirculated mixture onto the liquid in the bottom ofthe vessel, by the recirculation, or by paddles or the like provided inthe vessel for that purpose. The heating and recirculation of themixture are continued until substantially all the solvent is removedfrom the mixture. This may be readily determined by examining a sampleof the mixture to determine Whether the solids settle in the aqueousliquid and whether the odor of the solvent persists.

After removal of the solvent, the mixture comprises an aqueous liquid,finely divided solids therein, and other materials colloidally dispersedand/or dissolved therein. The solids include cellular material, cortexif not initially removed, proteinaceous materials which are insoluble inthe aqueous liquid and other insoluble materials. The colloidallydispersed and/or dissolved materials include solubilized prote naceousmaterials, sugars, mucilages, and other materials wholly or partiallysoluble in the liquid. This mixture may be used as such, or afterremoval of the aqueous liquid followed by washing and/or drying, forvarious purposes such as in compositions for binding, filling orcoating. However, the mixture is preferably further treated to producemore desirable products.

FURTHER TREATMENT OF DESOLVENTIZED MIXTURES The desolventized mixturemay be treated with a reagent which will precipitate solubilizedproteinaceous and other materials in the mixture, either in the presenceof the solids in the mixture or after the solids in the mixture havebeen removed from the aqueous liquid by filtration, centrifuging orotherwise. In either case, precipitation may be effected by adjustingthe pH value of the mixture to that at which the maximum precipitationof the solubilized or dispersed proteinaceous material in the liquidwill occur. This pH value varies with the nature of the residues beingtreated but, in general, is from about 3 to about 6. Thus, the pH valueat which maximum precipitation of proteinaceous material occurs from amixture derived from linseed is about 3.5; from castor residues the pHvalue is from about 3.8 to about 4.0, and from peanut or cottonseedresidues it is from about.4.0 to about 4.5.

After the precipitation of proteinaceous and other materials, theresulting mixture of solids in the aqueous liquid may be used as such orafter partial or complete removal of the aqueous liquid. Preferably, thesolids are separated from the aqueous liquid as by filtering orcentrifuging, and washed. The resulting solids, while wet or afterdrying, may be comminuted by pulverizing or grinding before use.

The liquid separated from the solids contains unprecipitatedproteinaceous and other materials. It may be discarded or processedfurther for recovery of useful products.

In general, greater amounts of proteinaceous materials can beprecipitated if the mixture, before the desolventizing step, has analkaline pH of from about 8 to about 13 and preferably from about 10 toabout 12. This causes greater solubilization and colloidal dispersion ofproteinaceous materials than is generally possible at other pH values.The precipitation is carried out by acidifying the desolventized mixtureto a pH value at which the maximum precipitation of the solubilizedand/or dispersed proteinaceous materials in the liquid occurs.

Of course, if the mixture prior to the precipitation step has a pH valuelower than about 8 but above the pH value at which maximum precipitationof the solubilized and/ or dispersed proteinaceous materials occurs,precipitation can nevertheless be effected by acidifying the mixture tothe pH value affording maximum precipitation.

On the other hand, if the mixture, before the precipitation treatment,has a pH value lower than that at which the maximum precipitation ofsolubilized and/or dispersed proteinaceous materials occurs, increasedprecipitation may be effected by treatment with a suitable alkalinematerial, such as those mentioned above, to raise the pH value to thatat which maximum precipitationof proteinaceous materials from themixture will occur.

The acidic material which may be employed to precipitate proteinaceousand other materials may be an acid or a compound capable of producing anacidic solution of the desired pH value. For best results, the acidicmaterial shouldnot form insoluble precipitates with the alkalinecompound present in the mixture. Examples of suitable acidic compoundsare sulfuric acid, hydrochloric acid, sulfurous acid, acetic acid, S02gas, and salts which produce acidic solutions.

FLOW DIAGRAMS Fig. '1 is a flow diagram illustrating one processaccording to the present invention. In this process the solvent-wettedresidues are mixed with an aqueous liquid, preferably an alkalinesolution, to form the mixture of solvent wetted residues and an aqueousliquid of the desired pH value. This mixture is then heated under vacuumwhile being agitated, to remove most and preferably all of the solventtherefrom. The resulting desolventized mixture containing solids wettedwith the aqueous liquid and colloidally dispersed and/or dissolvedmaterials, is then treated to separate the solids from the liquid as byfiltration or centrifuging. The separated solids C may be washed andused wet or dry, with or without further comminution. The separatedliquid is then treated, as by acidification, to precipitateproteinaceous and other materials. The resulting precipitated solids arethen separated from the liquid as by filtration or centrifuging, forexample in a solid bowl centrifuge. This separated liquid may bediscarded or further processed to recover unprecipitated proteinaceousor other materials therein. The separated solids A containing a largeproportion of proteinaceous material may be washed and used wet, orafter drying with or without further comminution.

Fig. 2 is a flow diagram illustrating another process according to thepresent invention. The steps of mixing the solvent-wetted residues withan aqueous liquid, preferably an alkaline solution, to form a mixture ofthe desired pI-I value, and the removal of solvent from the resultingmixture are similar to those described in connection with Fig. 1.However, in the process illustrated in Fig. 2, the desolventizedmixture, containing solids wetted with the aqueous liquid andcolloidally dispersed and/or dissolved materials, is treated, as byacidification, to precipitate proteinaceous and other precipitablematerials in the presence of the solids. The resulting mixture of solidsand aqueous liquid is then treated, as by filtering or centrifuging, forexample in a solid bowl centrifuge, to separate the solids from theliquid. The separated liquid may be discarded or further processed torecover unprecipitated proteinaceous or other materials containedtherein. The separated solids B comprisingprecipitated proteinaceous andother materials, and the solids, may be washed and used while wet orafter drying, with 'or withoutfurther comminution. v

PRODUCTS OF INVENTION u Product A The Product A of Fig. 1, comprisesthesolids precipitated from the solvent free, solid free aqueous liquid.This'product consists substantially entirely of proteinaceous material.It is free of cellular material, cortex, and other substances insolublein or not colloidally dispersed in the aqueous liquid. The nature andyield of the proteinaceous material is largely determined by the natureof the original solvent-Wetted residues, the amount of aqueous liquidmixed with such residues, the pH of the mixture, and the pI-ll value atwhich the precipitation is carried out. A product produced under optimumconditions for maximum precipitation after drying to a point where itcontains by weight from about 5% to about of water and other materialsreadily volatilizable at 110 C. will contain from about 14% to about 17%by weight of nitrogen. Substantially all of the nitrogen is combined inthe proteinaceous material which comprises a diificultly analyzablemixture of different proteins of different nitrogen contents. The Ofiicial and Tentative Methods of the Association of Oflicial AgricultureChemists, fourth edition, 1935, at page 335 directs the use of thefactor 6.25 for converting the weight of nitrogen, found by analysis, tothe approximate weight of protein. On this basis, it is apparent thatProduct A contains from about 87.5% to about 100% of proteinaceousmaterial.

A preferred product of this type consists essentially of theproteinaceous materials which were soluble or colloidally dispersible inan aqueous alkaline solution of about 8-13 pH and preferably of about10-12 pH; and which are preci itable by an acidic solution of about 3-6pH and-preferably of a pH value at which the maximum era,

10 cipitation of prbteinace'ous material will occur. Since theproteinaceous material need never be heated to temperatures greater thanabout 60 (2., there is substantially no degradation of the material.

The product is whitein color and may be readily dispersedand/ordiss'olved in alkaline solutions, and, hence, is useful inemulsion-type paints, coating compositions for paper or other materials,adhesives and other compositions. To maintain the high degree ofdispersibility, it is advantageous not to dry the product after itsproduction. Products of this type may also be used as foods, or asfillers for plastics or other materials, or in fertilizers.

Product B Another type of product, corresponding to Product 13 of Fig. 2comprises the initial solids and the solids precipitated from thesolvent free aqueous liquid. The amount of proteinaceous material in theproduct is determined by adjustment of certain factors,"such as theamount of aqueous liquid, the pH of the initial mixture, and the pHduring precipitation. A product produced from decorticatecl beans andseeds under optimum conditions for maximum precipitation and afterdrying to apoint where it contains by weight no more than about 5% toabout 10% of water and other materials readily volatilizable at 110 C.,will have the following typical approximate composition by "weight.

745% nitr'ogen' I 10-25% cellular material 5-10% moisture and substancesvolatilizable at In the case of undecorticated beans or seeds, theproduct willhave the following typical approximate composition byweight:

4%8% nitrogen 50%- cellular material and cortex 5%-10% moisture andsubstances volatilizable at 110 C.

Substantially all ofthe nitrogen in each case is combined .inproteinaceous materials. Converting by the factor 6.25, it is apparentthat the first product will contain from about 40% to about by weight ofproteinaceous material, and the second product will contain from about25% to about 50% by weight of proteinaceous material.

A product of this type contains these proteinaceous materials which areinsoluble in aqueous liquids of about 8-13 pH and those solubleproteinaceous materials which are precipitable by converting the pHvalue to that at which maximum precipitation of proteinaceous materialsoccurs.

At no stage in the process need the product be heated to a temperatureabove about 60 C., so that the product contains substantially undegradedmaterials. v

This product, preferably after comminution, may be employed for thepurposes indicated above for Product A. If used in emulsions, it isadvantageous to use a product which has never been dried. Since thepresence of the cortex and cellular material tends to impart a browncoloration to the product, it may not be as desirableforuse in paints orcoating materials as Product i v Product C Thepr oduqh, corresponding toProduct C of Fig. -1, comprises the "solids separated from thesolvent-free mixture prior to the precipitation step. Such solidscontain cellular material, cortex, if present in the original residue,and proteinaceous materials not solubilized by the aqueous liquid. Theamount of proteinaceous material present is dependent upon the pH of theinitial mixture, but in any event is much less than in Products A and B.

When a product produced from decorticated beans and seeds is dried to apoint where it contains no more than from about to about by weight ofwater and other materials readily volatilizable' at 110 C., it will havethe following typical approximate composition by weight:

0.8%-10% nitrogen 35%-85% cellular material 5%-10% moisture andsubstances volatilizable at 110 C.

In the case of undecorticated seeds and beans, the product will have thefollowing typical approximate composition by weight:

0.4%-4.0% nitrogen '75%-97% cellular material 5%10% moisture andsubstances volatilizable at 110 C.

In each of these products, substantially all of the nitrogen is combinedin proteinaceous material. Upon conversion by the factor of 6.25, it isapparent that the first product contains from about 5% to about 63% byweight of proteinaceous material, and the second product contains fromabout 2.5% to about by weight of proteinaceous material.

After washing and preferably after comminution, the product may be usedas a binder, filler for plastics or other materials, as a fertilizerand, in some cases, as stock food.

EXAMPLES The following examples illustrate processes and productsembodying the invention. Such examples are given only for illustrativepurposes and the invention is not to be limited thereto.

Example 1 The starting material was the solvent-wetted residue resultingfrom the extraction of oil with heptane from decorticated and crushedcastor beans. The heptane-wetted residues contained approximately 50%heptane and 50% solids by weight. The solids analyzed 11.2% nitrogen byweight (corresponding to approximately 70% proteinaceous material whencalculated as nitrogen 6.25) and the balance was finely divided cellularmaterial and water-soluble compounds. These residues were deposited in ahigh shear mixing vessel and a solution of sodium hydroxide of 11.0 pHwas slowly added while mixing .until a free-flowing slurry was obtained.This slurry was recirculated from a kettle through a pump and back to thmixing kettle while more of the alkali solution was added until a totalof about 17.5 pounds of water to each pound of heptane-wetted residuewas added. The mixture was then injected in a thin stream into the upperportion of a closed kettle in which a vacuum of about 28 inches ofmercury was maintained and which was heated with direct steam to atemperature of about C,.; solvent vapors together with some water vaporsflashed on the injected falling stream. Heating with direct steam wascontinued until a vapor tem perature of about 35 C. was reached. Themixture in the kettle was continuously agitated by recirculation of themixture from the lower portion of the kettle, through a pump, to theupper portion of the kettle to produce a splashing effect by the fallingstream. At this point a sample was withdrawn from the kettle and wasobserved to have the desired settling characteristics; i. e., the solidssettled in the liquid. Meanwhile, the solvent vapors evaporated from themixture, together with some water vapor, were withdrawn from the kettlethrough the vacuum pump and condensed at atmospheric pressure bycooling. The heptane was separated from the water for reuse in thesolvent extrac tion process. After the solids were found to settle out,the kettle was returned toatmospheric pressure. A 5% aqueous solution ofsulfuric acid was slowly added to the mixture while agitation wascontinued by recirculating the mixture through the pump. The acid wasadded until a sample was found to have a pH value of about 3.9. Thesolids in the mixture now comprised cellular materials and other solidmaterials initially present, as well as proteinaceous and othermaterials precipitated by the acid. The liquid contained solubleproteinaceous and other materials. The solids were then separated fromthe liquid by filtration, washed with 'water acidified to 3.9 pH,incompletely dried and pulverized.

The solids contained about 13.4% of nitrogen (equivalent to 86.3%proteinaceous material calculated as nitrogen 6.25), the balance beinglargely the finely divided cellular components of the originaldecortlcated castor bean. The proteinaceous material included both thealkali-insoluble proteinaceous material of the residue and that portionof the alkali-soluble proteinaceous materials which was precipitated bythe acid.

The product dispersed readily in various aqueous alkaline solutions andis useful as a base for emulsion paints, coating materials, adhesivesand for other purposes.

Example 2 Heptane-wetted castor residues from decorticated castor beans,of the kind described in Example 1, were desolventized under theconditions set forth in Example 1. The desolventized mixture was thencentrifuged in a solid bowl centrifuge to separate solids from liquids.The separated solids, after neutralization with acid and drying,contained about 1.1% nitrogen (equivalent to 6.87% proteinaceousmaterial calculated as nitrogen 6.25), the balance being largelycellular material. These solids were found to be useful as a fertilizerand as filler materials for plastics.

The clear liquid separated from the solids in the centrifuging operationwas then acidified by the addition of 5% solution of sulfuric acid tothe point of maximum precipitation (about 3.9 pH), de-watered bydecantation and washed with water acidified to 3.9 pH. The precipitatedsolids were then separated from the liquid by filtration, incompletelydried and pulverized. The resulting product contained 16.1% nitrogen byweight (approximately proteinaceous material calculated as nitrogen6.25). It was easily dispersible in alkaline solutions and is useful asan emulsion base for paints, coating materials, as a hinder or adhesive,and as a filler for plastics and the like.

Example 3 in the residue analyzed6.1-% nitrogen (equivalent to 38.1%proteinaceous material calculated as nitrogenX 6.25). To theheXane-wetted meal in a high shear mixing vessel water was addedinproportions of 25 parts of water to each-part of solvent-wetted meal byweight. The relatively large amount of water was used to obtain aworkable slurry in view of the high proportion of mucilages present inthe meal. Suificient caustic soda was added to give the mixture a pHvalue of about 11. The mixture was thoroughly agitated and mixed byrecirculating through a pump.

The mixture was then heated in a desolventizing vessel undertheconditions outlined in Example 1. When a temperature of 35 C. wasobtained, the solids ina withdrawn sample were Example 4 Heptane-wettedresidues of'the kind described in Example '3 were mixed with alkalisolution and desolventized as insaidexample. The desolventized mixturewas then subjected to a separating operation by centrifuging in a solidbowl centrifuge. The separated solids, after washing, 4 were dried andpulverized; they comprised largely cortex, cellular material, and about11.2% by weight of alkali-insoluble proteinaceous material. These solidsare useful as a stock feed, fertilizer, Or binding material.

The liquids separated during the centrifuging operation were treatedwith 5% sulfuric acid solution until a pH value of about 3.5 wasreached; a considerable precipitation occurred. The precipitated solidswere then separated from the liquids by a solid bowl centrifuge, andwere then washed with water acidified to 3.5 pH, dried and pulverized.The pulverized product contained 15.4 nitrogen (approximately 96.25%proteinaceous material calculated as nitrogen 6.25). The product wasfound to have excellent color and dispersed readily in alkalinesolutions. It is useful in paints, coating materials, adhesives, as afiller, and as a food.

Example 5 The process of this example is identical with that of Example1, except that the solids separated from the liquid by filtration werenot dried. The filter cake was washed on the filter and then removed; itcontained by weight 17.5% solids and 82.5% water. The solids containedabout 13.5% of nitrogen (corresponding to about 87% proteinaceousmaterial calculated as nitrogen 6.25).

The resulting product was then formed. .into an emulsion without everhaving'been dried. .To 540 ,parts by weight .of this water-wet ,productwas added 20 parts of rosin ,and .20 partsof linseed fatty acids, andthe whole was heatedat about F. for .30 minutes While .being agitated.Then 10 parts vof a sodium .salt .of va chlorinated phenol was addedas'a preservative and the temperature was raised to about To theresulting mixture was added .8 parts of borax and sufiicient ammoniumhydroxide to raise the pI-I value .to 9,. The resulting dispersion wasthen heated to about F. for45rminutes, cooled and readjusted to a pHvalue of ,9 with ammonium hydroxide. ,It was ,found 130 be excellent foruse .as a base for emulsion paints orpaper coating materials. For the,production of such compositions, pigments, oily vehicles 'or otherdesired components can be incorporated in the dispersion during or afterits preparation.

It was also found that the water-wet pro-- teinaceous product could bestored wet for long periods of time without deterioration, particularlywhen it contained a protein preservative,

such as the chlorinated phenol mentioned above- The present inventionthus provides processes by which solvents may be rapidly,-efiicientlyand economically recovered from solvent-wetted residues remaining aftersolvent extraction of oils from oil-containing vegetable materials,which processes do not require the use of high temperatures which woulddeleteriously affect proteinaceous materials in the residues. Theprocessesproduce ,at a low cost useful and valuable products of highlydesirable properties :from such residues. Such processes may be carriedout in conventional equipment.

The present invention also provides novel products containing highproportions of proteinaceous materials having highly desirableproperties.

It is apparent that the solvent-wetted vegetable residues employed asthe starting material need not necessarily be those resulting fromsolvent extraction of vegetable materials to re-' move oils therefrom.Moreover, the solventwetted residues may be mixtures of diiferentsolvent-wetted residues; thus, they maybe mixtures of residues ofdifferent vegetable materials, or residues wetted with differentsolvents. Also dispersing and precipitating agents other than thoseindicated may be employed.

The above description of the invention is merely illustrative and theinvention is to be limited only by the scope of the appended claims.

What is claimed is:

1. The process for removing oil-miscible solvents from solvent-wettedvegetable residues containing proteinaceous constituents, comprisingmixing a solvent-wetted residue with an aqueous liquid to form a slurry,and evaporating the solvent from said mixture at a temperature belowthat at which degradation of the proteinaceous constituents will occur.

2. A process for removing oil-miscible solvents from solvent-wettedvegetable residues while preventing degradation of the proteinaceousconstituents of said residues comprising mixing a solvent-wetted residuewith an aqueous liquid to form a slurry having a pH value of from about5 to about 13 and evaporating the solvent therefrom at a temperaturebelow that at which degradation of the proteinaceous constituents willoccur.

3. A process as claimed in claim 2 wherein 15 the mixture has a pH valueof from about 5 to about 8.

4. A process as claimed in claim 2 wherein the mixture has a pH value offrom about 8 to about 13.

5. A process as claimed in claim 2 wherein the mixture has a pH value offrom about 10 to about 12.

6. A process for removing oil miscible solvents from solvent-wettedvegetable residues containing proteinaceous material comprising mixing asolvent-wetted residue with an aqueous liquid to form a slurry, heatingthe mixture while under a partial vacuum, to a temperature below thatwhich will degrade the proteinaceous material to evaporate substantiallyall of the solvent therefrom.

'7. A process as claimed in claim 6 wherein the mixture has a pH valueof from about 10 to about 12 and wherein the mixture is heated to atemperature not higher than about 60 C.

8. A process for treating solvent-wetted vegetable residues containingproteinaceous materials comprising mixing a solvent-wetted residue withan aqueous liquid to form a' slurry of solids in liquids having a pHvalue at which at least a portion of the proteinaceous material will besolubilized in said liquids, evaporating substantially all of thesolvent from said mixture at such temperature and pressure that thedegradation of the proteinaceous material therein will be prevented, andchanging the pH value of the desolventized liquid to precipitate atleast a portion of the solubilized proteinaceous material.

9. A process as claimed in claim 8 wherein the mixture of solvent-wettedresidue and aqueous liquid has a pH value of from about 5 to about 13and wherein the pH value of the desolventized liquid is lowered toprecipitate solubilized proteinaceous material from said liquid.

10. A process as claimed in claim 8 wherein the aqueous liquid isalkaline and the mixture has a pH value of from about 8 to about 13 andwherein the pH value of the desolventized liquid is lowered to a valueof from about 3 to about 6 by the addition of an acidifying reagentwhereby substantial amounts of the solubilized proteinaceous material isprecipitated.

11. A process for treating solvent-wetted vegetable residues containinproteinaceous materials comprising mixin a, solvent-wetted residue withan aqueous liquid to form a slurry of solids in liquids having a pHvalue at which at least a portion of the proteinaceous material will besolubilized in said liquids, evaporating substantially all of thesolvent from said mixture at such temperature and pressure thatdegradation of the proteinaceous material therein will be prevented,separating the solids from the desolventized liquid, and changing the pHvalue of the substantially solid-free desolventized liquid toprecipitate at least a portion of the solubilized proteinaceousmaterial.

12. A process as claimed in claim 11 wherein the mixture ofsolvent-wetted residue and aqueous liquid has a pH value of from about 5to about 13 and wherein the pH value of the desolventized liquid islowered to precipitate solubilized proteinaceous material from saidliquid.

13. A process as claimed in claim 11 wherein the aqueous liquid isalkaline and the mixture has a pI-i value of from about 8 to about 13and wherein the pH value of the desolventized liquid is lowered to avalue of from about 3 to about 6 by the addition of an acidifyingreagent whereby substantial amounts of the solubilized proteinaceousmaterial is precipitated.

14. A process for treating nolvent-wetted vegetable residues containingproteinaceous materials comprising mixing a solvent-wetted residue withan aqueous liquid to form a slurry of solids in liquids having a pHvalue at which at least a portion of the proteinaceous material will besolubilized in said liquids, evaporating substantially all of thesolvent from said mixture at such temperature and pressure thatdegradation of the proteinaceous material therein will be prevented,changing the pH value of the desolventized liquid to precipitate atleast a portion of the solubilized proteinaceous material and removing asubstantial amount of the liquid from the solids and precipitatedproteinaceous material.

1 HAROLD F. SAUNDERS.

REFERENCES CITED The following references are of record in the file ofthis patent:

1. THE PROCESS FOR REMOVING OIL-MISCIBLE SOLVENTS FROM SOLVENT-WETTED VEGETABLE RESIDUES CONTAINING PROTEINACEOUS CONSTITUENTS, COMPRISING MIXING A SOLVENT-WETTED RESIDUE WITH AN AQUEOUS LIQUID TO FORM A SLURRY, AND EVAPORATING THE SOLVENT FROM SAID MIXTURE AT A TEMPERATURE BELOW THAT AT WHICH DEGRADATION OF THE PROTEINACEOUS CONSTITUENTS WILL OCCUR. 